In medicine and physiology, sensing electrodes are frequently connected to monitoring instruments which record, analyze, display, process, or otherwise monitor physiological signals generated by such sensing electrodes. Sensing electrodes are placed at specific locations on a patient's body to sense signals occurring at such locations, and coupled to an appropriate monitoring instrument to produce useful physiological output information such as an electrocardiogram (ECG), electroencephalogram (EEG), or electromyogram (EMG).
The present invention is particularly but not exclusively useful in encephalograhic or brain wave monitoring using electrodes attached to a patient's head and connected to an EEG machine, which is a monitoring instrument used for the analysis and display of signals generated by such sensing electrodes. In this application, the connection of the sensing electrodes to the monitoring instrument is made through a connection box commonly called a "headbox" since it is located near the patient's head. Sensing electrode assemblies used for EEG typically comprise a metal disk which is glued to a patient's head or a needle which is inserted into a patient's head subcutaneously. The disk or needle is connected to one end of a wire conductor which has a connector portion such as a standard pin plug connected to the other end of the conductor. This connector portion is adapted to be detachably connected to a mating connector portion in the headbox, such as a jack which mates with a pin plug. Such electrode assemblies are referred to typically and herein as "electrodes." Also in this disclosure, both connector portions and the connector assembly formed when such portions are mated may be referred to as "connectors." Such connectors include conductors in each portion which contact mating conductors in order to couple signals present on one connector portion to the mating connector portion.
In conventional apparatus, the headbox is merely a box with connectors such as electrical jacks which receive electrode connectors such as standard pin plugs. The headbox may have a stylized picture of a head on it to indicate which electrode pin plug is to be placed into which jack. Headboxes may also have pre-amplifiers contained within them which amplify the low voltage EEG signals for transmission along a cable from the headbox output to the input in the monitoring instrument.
EEG machines are large, complicated instruments and thus are desirably operated by trained technologists. In the prior art, the headbox used with such machines is typically connected to a switch panel on the EEG machine having an array of switches which allows connection of any electrode to any channel input of the EEG machine This array of switches may be controlled manually or by computer software. EEG technologists are trained as to where to place electrodes on a patient's head, how to switch the electrodes into the EEG machine input channels, and how to set up the EEG machine for the particular medical procedure being performed.
Brain wave monitoring is increasingly being performed by physicians and hospital personnel who are not specifically trained in electroencephalography. Examples of such monitoring include surgical monitoring, where the EEG machine is typically operated by an anesthesiologist, and in intensive care units (ICU's) where the EEG machine may be operated by a nurse. In these settings, it is extremely important to make the operation of the brain monitoring equipment as easy as possible so that appropriate and accurate monitoring is accomplished.
Conventional EEG machines and more specialized brain wave monitors are difficult to use by those not trained in EEG technology, in part due to the setup procedures involved. Such difficulties associated with EEG monitoring procedures include selecting the number of electrodes and determining the correct location for their attachment to the body for each different monitoring procedure; switching the electrodes into the correct monitoring instrument inputs for each different monitoring procedure; setting up the monitoring instrument for the correct processing and displays for each different monitoring procedure; and having to set up another monitor with the same parameters when the patient is moved from one room to another room or from the operating room ("OR") to the ICU. Similar difficulties also are found in other types of monitoring such as ECG and EMG monitoring.